Octane/station???
 

I was filling up my Z yesterday and I bumped in to my friend at the station. He was just finishing up his 2012 M3coupe and he asked me what octane I was using. Told him that I used what the manual tells me to use. Then he told me to get it tuned for 94octane, it's much better. I don't know much about the octane stuff but I know if I use lower octane than I'm supposed to the engine will misfire or sum thing. Also I saw on the pump there's like a 10% ethenhol or something. So getting it tuned for 94 is better for the car long term or it doesn't matter? It's only 3 cents different from what I use.

shell 91 octane! best gas

If you have access to the higher octane gas, you do get an improvement with a proper tune. The manual recommends 91 or higher, so don't use anything below that or you could get knocks and pings. I always use 93 or higher, but availability varied depending on where you live.

I don't have a tune for 94but I use 91. What happens if I use 94 without a tune?

You may see a slight improvement in performance because your timing may advance a bit. The higher the octane the more timing advance up to a limit. For the extra couple bucks per tank full I'd keep using the 94 octane. I wish we had it. The best available here is 91.

In B.C. alot but not all Chevrons have 94 with no ethanol.

I'm tuned for 94 octane @ 27psi and 25psi on 91 octane. Both from Petro Canada.

Double check with teh gas companies - but in Ontario Shell V Power gold is the only one with no ethanol. Sunoco/ Husky / Petro Can 94 does have some ethanol - nit so good for cars that see limited use or sit in storage as it can attract moisture. Really do not believe you will see a difference in running 91 vs 94 octance - as it is up to so many setting on the cars computers to adjust how it runs on the fuel. Manual and Nissan call for 91 so use that - ideally Shell.

What does that 10% ethanol do?

You should the run the engine at the recommended octane for max performance benefit. Higher won't hurt (but unless your tuned for it - a waste of money and zero benefit), lower will hurt your engine.

Eberything You Ever Wanted To Know About Octane

I'm with Spitfiretr7 - Shell is the best. I believe the 370 manual even says to stay away from ethanol fuels. It's just an additive to make gas cheaper but in the end, not as good as pure gas. I know Shell's V power is pure, I thought Petro Can was too.

Biofuel additive that cuts down emmisions.

Also cuts down my lawnmower and snoblowers carbs (eats thru the floats). local small engine repair guy loves the ethanol. Seen a news report on how the EPA wants to up it to 15%. A rep from the oil industry was saying how that percentage will hurt engines. Cars are not engineered to handle 15%.

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Lol 15% will kill most of the old cars!

94 octane can be a benefit if there are times when the engine is under a load like going up a grade and it starts to ping. Well, you won't hear it because the anti-knock sensor will detect the ping and retard the timing a few degrees or so. That is a decrease in performance. The 94 octane may not make the engine ping and hence the engine timing will not retard. There is nothing wrong with using 94 octane but it may not be worth it as others have mentioned unless you change the timing map in the ecu using something like Uprev if the timing map can in fact be altered. My 'vette would benefit a great deal because I can alter the timing curve relatively easy.

our wonderful government subsidizes corn growers and between politicians and the epa, they know more than the car manufactures what is best for our cars! NOT!

As Dizzy said, Shell 91 is the best. Too bad they don't offer 94 for those who tuned for it :(